It is different on the touring bikes that give you a carb/EFI choice but the same on Softails that have a choice. The touring EFI bikes have higher ratios which would mean higher RPMs for a given speed...about 7%. My guess is that the torque curves are a little different for the two and they are just tweaks. I suppose it could also have to do with the slightly higher EFI idle speed. Disclaimer: the preceeding is a wild guess.